Alloy‐Type Anode Materials for Sodium‐Ion Batteries: From Single Metals to MultiComponent Alloys

ABSTRACT

Sodium‐ion batteries (SIBs) are widely regarded as a promising alternative to lithium‐ion batteries due to their abundant sodium resources, broad geographical distribution, and low cost, rendering them particularly attractive for large‐scale energy storage applications. However, the development of anode materials that simultaneously deliver high energy density, long cycle life, and robust safety remains a critical challenge for the commercialization of SIBs. Currently, SIB anode materials can be generally classified into intercalation‐type, conversion‐type, and alloy‐type materials. Although intercalation‐type anodes suffer from limited capacity and conversion‐type materials are often plagued by poor electronic conductivity and severe voltage hysteresis, alloy‐type anodes have attracted increasing attention due to their high theoretical capacities, suitable operating potentials, and favorable intrinsic conductivity. Nevertheless, single‐metal alloy anodes (e.g., Sn, Bi, and Sb) typically undergo severe volume expansion during sodiation, leading to structural degradation and rapid capacity fade. To address these issues, extensive efforts have been devoted to developing modification strategies, including carbon compositing, structural engineering, electrolyte optimization, and the design of multicomponent alloy systems. In this review, we provide a comprehensive and systematic overview of alloy‐type anode materials for SIBs, covering single‐metal, binary (active–active and active–inactive), ternary, and higher‐order alloy‐type anode systems. The fundamental sodium storage mechanisms are summarized, while composition regulation strategies and structural design principles are critically discussed. Finally, the remaining challenges and future research directions toward practical applications are highlighted. This review aims to offer valuable insights into the rational design of high‐performance and commercially viable alloy‐type anodes for next‐generation sodium‐ion batteries.